delphi send key into an invisible process

Question

The goal is to send the Q key press to an invisible process (that does not have focus) : I know the process ID.

I know how to send keys to a visible application. Can this be done to an hidden application ?

Somewhat related: http://stackoverflow.com/questions/3688235/how-can-i-set-a-hot-key-winkey-combination-to-call-an-application — Andreas Rejbrand, Aug 14 '11 at 17:00
You can send keystrokes to any process if you have the process id. Whether or not the process will do something with it, depends on the process. Though you will probably have to get its handle first using the process id. — Marjan Venema, Aug 14 '11 at 17:56
@Marjan how can you send a keystroke to a process that has no windows ? — opc0de, Aug 14 '11 at 19:08
@Marjan: yes, somewhat. That question asks for a way to set a system wide key. — Rudy Velthuis, Aug 14 '11 at 23:20

score 1 · Answer 1 · answered Aug 16 '11 at 13:11

I assume, that your invisible process has a window, which just happen to be invisible (it could for example have been hidden through a call to ShowWindow with SW_HIDE als parameter) and that you want to send keystrokes using SendMessage/PostMessage.

I would suggest to try the following:

Enumerate all main windows using EnumWindows.
For each window check if it belongs to your process using GetWindowThreadProcessId.
As soon as you have found the main window of your process, send your Keystrokes using SendMessage or PostMessage.

A hidden window should be able to receive keystokes as good as a visible window and most application probably don't check if they are really visible before reacting, so that there are good chances that it works.

delphi send key into an invisible process

1 Answers1